Re: [PATCH v3 2/3] dt-bindings: firmware: add mbedtee,tee binding

On Mon, Jul 20, 2026 at 03:35:56PM +0800, Xing Loong wrote:

MbedTEE is a Trusted Execution Environment for embedded systems (https://github.com/mbedtee). It communicates with the REE via shared-memory ring buffers using a fixed RPC protocol. Two platform configurations are supported:

• ARM/AArch64 (TrustZone, SMC): two reserved-memory regions (t2r-ring and t2r-shm) plus a GIC SPI edge interrupt for TEE-to-REE notifications.
• RISC-V (IMSIC): three reserved-memory regions, adding r2t-ring for REE-to-TEE command submissions; no interrupts property (T2R notifications use IMSIC MSI allocated at runtime).

Signed-off-by: Xing Loong xing.xl.loong@gmail.com

Changes in v3:

• Drop all phandle stub nodes from examples.
• Remove redundant required: - interrupts from then branch.
• Simplify title and description.

Changes in v2:

• Fix DT binding review comments from Krzysztof Kozlowski:
  • Drop $nodename, "YAML devicetree binding" wording, property descriptions
  • Rename compatible string to mbedtee,tee
  • Rename memory regions: rpc-t2r-ring -> t2r-ring, rpc-t2r-shm -> t2r-shm, rpc-r2t-ring -> r2t-ring
  • Add memory-region / memory-region-names to required
  • Simplify allOf constraints (drop redundant else-branch items)
  • Rewrite description to describe hardware/firmware, not the binding or driver
  • Drop all irrelevant platform nodes (gic, cpus, reserved-memory)
  • Add maxItems: 1 constraint to interrupts property (Sashiko AI review)

---

.../bindings/firmware/mbedtee,tee.yaml | 109 ++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml

diff --git a/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml b/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml new file mode 100644 index 0000000..a8f1201 --- /dev/null +++ b/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml @@ -0,0 +1,109 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/firmware/mbedtee,tee.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: MbedTEE

+maintainers:

• • Xing Loong xing.xl.loong@gmail.com

+description: |

• MbedTEE is a Trusted Execution Environment for embedded systems.
• It communicates with the REE (Linux) via shared-memory ring
• buffers using a fixed RPC protocol.
• We're using "mbedtee" as the vendor prefix for the open-source TEE
• project at https://github.com/mbedtee.
• The REE and TEE CPUs sharing the RPC memory must be in a
• hardware-coherent domain.
• Two or three reserved-memory regions are required:
• t2r-ring: ring buffer for TEE-to-REE notifications
• t2r-shm: shared memory for TEE-to-REE RPC payloads
• r2t-ring: ring buffer for REE-to-TEE command submissions (RISC-V)

Put any details about specific properties with the property schema.

• On ARM the transport uses SMC and a GIC SPI interrupt. On RISC-V
• the transport uses shared-memory rings and IMSIC MSI; the TEE
• polls r2t-ring for commands from the REE.

+properties:

• compatible:
• const: mbedtee,tee
• interrupts:
• maxItems: 1
• msi-parent:
• maxItems: 1
• memory-region:
• minItems: 2
• maxItems: 3
• memory-region-names:
• minItems: 2
• maxItems: 3
• items:

•  enum:
  

•    - t2r-ring
  

•    - t2r-shm
  

•    - r2t-ring
  

Needs to define the order as sashiko points out. The order doesn't change, so it doesn't need to be defined in the if/then schemas.

+required:

• • compatible
• • memory-region
• • memory-region-names

+allOf:

• • if:

•  required:
  

•    - interrupts
  

• then:

•  properties:
  

•    msi-parent: false
  

•    memory-region:
  

•      maxItems: 2
  

•    memory-region-names:
  

•      items:
  

•        - const: t2r-ring
  

•        - const: t2r-shm
  

Just 'maxItems: 2'

• else:

•  required:
  

•    - msi-parent
  

•  properties:
  

•    interrupts: false
  

•    memory-region:
  

•      minItems: 3
  

•    memory-region-names:
  

•      items:
  

•        - const: t2r-ring
  

•        - const: t2r-shm
  

•        - const: r2t-ring
  

Just 'minItems: 3'

+additionalProperties: false

+examples:

• • |
• #include <dt-bindings/interrupt-controller/arm-gic.h>
• firmware {

•    mbedtee {
  

•        compatible = "mbedtee,tee";
  

•        interrupts = <GIC_SPI 72 IRQ_TYPE_EDGE_RISING>;
  

•        memory-region = <&t2r_ring>, <&t2r_shm>;
  

•        memory-region-names = "t2r-ring", "t2r-shm";
  

•    };
  

• };
• • |
• firmware {

•    mbedtee {
  

•        compatible = "mbedtee,tee";
  

•        msi-parent = <&imsic>;
  

•        memory-region = <&t2r_ring>, <&t2r_shm>, <&r2t_ring>;
  

•        memory-region-names = "t2r-ring", "t2r-shm", "r2t-ring";
  

•    };
  

• };

-- 2.43.0